I'm also running a 950R and figure it's only a matter of time before the supply of OS1 premounts dries up. I'd also be interested in donuts, since the wheels can still be had pretty cheaply. Worst case, I'll have to buy the tires premounted on the Kyosho/Mugen wheel, soak 'em in thinner to remove the rubber, and remount them on the correct wheels.....brings back some messy memories.